The present invention relates to a multi-piece solid golf ball excellent in resilience, controllability, feel of hitting, and durability.
Golf balls have been requited to be excellent in resilience and thereby flight performance, feel of hitting upon shots, durability, and controllability, and to meet such requirements, various kinds of golf balls have been proposed, for example, in Japanese Patent Laid-open Nos. Hei 7-24085, Hei 9-239068, and Hei 10-151226.
The use of silicone materials for producing golf balls has been proposed, for example, in Japanese Patent Laid-open No. 2001-170213, and U.S. Pat. Nos. 6,159,110, 6,162,134, and 6,204,331. Such golf balls using silicon materials, however, have been recently required by golf players to be further improved in terms of resilience, feel of hitting, durability, and controllability.
In view of the foregoing, the present invention has been made, and an object of the present invention is to provide a multi-piece golf ball excellent in resilience and thereby flight performance, controllability, feel of hitting, and durability.
To achieve the above object of the present invention, according to an aspect of the present invention, there is provided a multi-piece golf ball including: a core having a diameter of 30 to 40 mm, the core being made from a rubber composition mainly containing polybutadiene; at least one intermediate layer including the outermost layer having a thickness of 0.5 to 2.0 mm, the outermost layer being made from a resin material containing an ionomer resin in an amount of 30% by weight or more; and a cover having a thickness of 0.5 to 2.0 mm, the cover being made from a material obtained by dispersedly blending at least one kind of silicone powder selected from a silicone rubber powder, a silicon resin powder, and a composite powder thereof, in a main resin component containing an ionomer resin in an amount of 50% by weight or more; wherein the hardness of the cover is smaller than the hardness of the outermost layer of the at least one intermediate layer and is larger than the hardness of a center portion of the core.
An average particle size of the silicon powder is preferably in a range of 0.5 to 700 xcexcm.
The content of the silicon powder is preferably in a range of 0.5 to 20 parts by weight on the basis of 100 parts by weight of the main resin component.
The center portion of the core preferably has a Durometer D hardness in a range of 25 to 45.
The outermost layer of the at least one intermediate layer preferably has a Durometer D hardness in a range of 50 to 70.
The cover preferably has a Durometer D hardness in a range of 45 to 60.
At least one of the resin material forming the outermost layer of the at least one intermediate layer and the main resin component forming the cover preferably contains a thermoplastic elastomer having a crystalline polyethylene block.
At least one of the resin material forming the outermost layer of the at least one intermediate layer and the main resin component forming the cover preferably contains an ethylene-(meth)acrylic acid-acrylate copolymer.
The total thickness of the outermost layer of the at least one intermediate layer and the cover is preferably in a range of 1.2 to 3.8 mm.
At least one kind of silicon powder selected from a silicon rubber powder, a silicon resin powder, and a composite powder thereof is preferably dispersedly blended in the resin material forming the outermost layer of the at least one intermediate layer.
According to the golf ball of the present invention, since the silicone powder is dispersedly blended in the cover and further the at least one intermediate layer is harder than the cover and the core, it is possible to improve the resilience and thereby flight performance, and temperature dependency of the ball. In addition, since the two outer layers (the cover and the outermost layer of the at least one intermediate layer) are each formed from a material mainly containing an ionomer resin to thereby enhance adhesiveness between these outer layers, it is possible to reduce the energy loss, and since the cover is softer than the at least one intermediate layer, it is possible to significantly improve the durability against cracking upon shots. Also since the cover is softer than the at least one intermediate layer, it is possible to improve the spin characteristic of the golf ball, and since the core is relatively soft, it is possible to make deformation of the golf ball large and hence to improve the controllability of the golf ball. Further, since the cover is soft and the core is relatively soft, it is possible to ensure a soft feel of hitting the golf ball.